/Engine/Source/Runtime/Engine/Classes/Components/PrimitiveComponent.h
Set the center of mass of a single body. This will offset the physx-calculated center of mass. Note that in the case where multiple bodies are attached together, the center of mass will be set for the entire group.
void SetCenterOfMass ( FVector CenterOfMassOffset, [FName](API\Runtime\Core\UObject\FName) BoneName )